[x86] Make the 'x86-64' cpu, what I see as and many use as the generic
[oota-llvm.git] / lib / Target / X86 / X86.td
index 923f894970172715eaeb63ba4b928999687ac10f..d01e4621616e34eb22d8cbf6acd26f35fda8f226 100644 (file)
@@ -1,14 +1,14 @@
-//===- X86.td - Target definition file for the Intel X86 ---*- tablegen -*-===//
-// 
+//===-- X86.td - Target definition file for the Intel X86 --*- tablegen -*-===//
+//
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
-// 
+//
 //===----------------------------------------------------------------------===//
 //
-// This is a target description file for the Intel i386 architecture, refered to
-// here as the "X86" architecture.
+// This is a target description file for the Intel i386 architecture, referred
+// to here as the "X86" architecture.
 //
 //===----------------------------------------------------------------------===//
 
 include "llvm/Target/Target.td"
 
 //===----------------------------------------------------------------------===//
-// X86 Subtarget features.
+// X86 Subtarget state
+//
+
+def Mode64Bit : SubtargetFeature<"64bit-mode", "In64BitMode", "true",
+                                  "64-bit mode (x86_64)">;
+def Mode32Bit : SubtargetFeature<"32bit-mode", "In32BitMode", "true",
+                                  "32-bit mode (80386)">;
+def Mode16Bit : SubtargetFeature<"16bit-mode", "In16BitMode", "true",
+                                  "16-bit mode (i8086)">;
+
+//===----------------------------------------------------------------------===//
+// X86 Subtarget features
 //===----------------------------------------------------------------------===//
 
 def FeatureCMOV    : SubtargetFeature<"cmov","HasCMov", "true",
                                       "Enable conditional move instructions">;
 
+def FeaturePOPCNT   : SubtargetFeature<"popcnt", "HasPOPCNT", "true",
+                                       "Support POPCNT instruction">;
+
 
 def FeatureMMX     : SubtargetFeature<"mmx","X86SSELevel", "MMX",
                                       "Enable MMX instructions">;
 def FeatureSSE1    : SubtargetFeature<"sse", "X86SSELevel", "SSE1",
                                       "Enable SSE instructions",
                                       // SSE codegen depends on cmovs, and all
-                                      // SSE1+ processors support them. 
+                                      // SSE1+ processors support them.
                                       [FeatureMMX, FeatureCMOV]>;
 def FeatureSSE2    : SubtargetFeature<"sse2", "X86SSELevel", "SSE2",
                                       "Enable SSE2 instructions",
@@ -40,14 +54,15 @@ def FeatureSSE3    : SubtargetFeature<"sse3", "X86SSELevel", "SSE3",
 def FeatureSSSE3   : SubtargetFeature<"ssse3", "X86SSELevel", "SSSE3",
                                       "Enable SSSE3 instructions",
                                       [FeatureSSE3]>;
-def FeatureSSE41   : SubtargetFeature<"sse41", "X86SSELevel", "SSE41",
+def FeatureSSE41   : SubtargetFeature<"sse4.1", "X86SSELevel", "SSE41",
                                       "Enable SSE 4.1 instructions",
                                       [FeatureSSSE3]>;
-def FeatureSSE42   : SubtargetFeature<"sse42", "X86SSELevel", "SSE42",
+def FeatureSSE42   : SubtargetFeature<"sse4.2", "X86SSELevel", "SSE42",
                                       "Enable SSE 4.2 instructions",
                                       [FeatureSSE41]>;
 def Feature3DNow   : SubtargetFeature<"3dnow", "X863DNowLevel", "ThreeDNow",
-                                      "Enable 3DNow! instructions">;
+                                      "Enable 3DNow! instructions",
+                                      [FeatureMMX]>;
 def Feature3DNowA  : SubtargetFeature<"3dnowa", "X863DNowLevel", "ThreeDNowA",
                                       "Enable 3DNow! Athlon instructions",
                                       [Feature3DNow]>;
@@ -57,34 +72,114 @@ def Feature3DNowA  : SubtargetFeature<"3dnowa", "X863DNowLevel", "ThreeDNowA",
 def Feature64Bit   : SubtargetFeature<"64bit", "HasX86_64", "true",
                                       "Support 64-bit instructions",
                                       [FeatureCMOV]>;
+def FeatureCMPXCHG16B : SubtargetFeature<"cx16", "HasCmpxchg16b", "true",
+                                      "64-bit with cmpxchg16b",
+                                      [Feature64Bit]>;
 def FeatureSlowBTMem : SubtargetFeature<"slow-bt-mem", "IsBTMemSlow", "true",
                                        "Bit testing of memory is slow">;
+def FeatureSlowSHLD : SubtargetFeature<"slow-shld", "IsSHLDSlow", "true",
+                                       "SHLD instruction is slow">;
 def FeatureFastUAMem : SubtargetFeature<"fast-unaligned-mem",
                                         "IsUAMemFast", "true",
                                         "Fast unaligned memory access">;
 def FeatureSSE4A   : SubtargetFeature<"sse4a", "HasSSE4A", "true",
-                                      "Support SSE 4a instructions">;
-
-def FeatureAVX     : SubtargetFeature<"avx", "HasAVX", "true",
-                                      "Enable AVX instructions">;
-def FeatureCLMUL   : SubtargetFeature<"clmul", "HasCLMUL", "true",
-                               "Enable carry-less multiplication instructions">;
-def FeatureFMA3    : SubtargetFeature<"fma3", "HasFMA3", "true",
-                                     "Enable three-operand fused multiple-add">;
+                                      "Support SSE 4a instructions",
+                                      [FeatureSSE3]>;
+
+def FeatureAVX     : SubtargetFeature<"avx", "X86SSELevel", "AVX",
+                                      "Enable AVX instructions",
+                                      [FeatureSSE42]>;
+def FeatureAVX2    : SubtargetFeature<"avx2", "X86SSELevel", "AVX2",
+                                      "Enable AVX2 instructions",
+                                      [FeatureAVX]>;
+def FeatureAVX512   : SubtargetFeature<"avx512f", "X86SSELevel", "AVX512F",
+                                      "Enable AVX-512 instructions",
+                                      [FeatureAVX2]>;
+def FeatureERI      : SubtargetFeature<"avx512er", "HasERI", "true",
+                      "Enable AVX-512 Exponential and Reciprocal Instructions",
+                                      [FeatureAVX512]>;
+def FeatureCDI      : SubtargetFeature<"avx512cd", "HasCDI", "true",
+                      "Enable AVX-512 Conflict Detection Instructions",
+                                      [FeatureAVX512]>;
+def FeaturePFI      : SubtargetFeature<"avx512pf", "HasPFI", "true",
+                      "Enable AVX-512 PreFetch Instructions",
+                                      [FeatureAVX512]>;
+
+def FeaturePCLMUL  : SubtargetFeature<"pclmul", "HasPCLMUL", "true",
+                         "Enable packed carry-less multiplication instructions",
+                               [FeatureSSE2]>;
+def FeatureFMA     : SubtargetFeature<"fma", "HasFMA", "true",
+                                      "Enable three-operand fused multiple-add",
+                                      [FeatureAVX]>;
 def FeatureFMA4    : SubtargetFeature<"fma4", "HasFMA4", "true",
-                                      "Enable four-operand fused multiple-add">;
+                                      "Enable four-operand fused multiple-add",
+                                      [FeatureAVX, FeatureSSE4A]>;
+def FeatureXOP     : SubtargetFeature<"xop", "HasXOP", "true",
+                                      "Enable XOP instructions",
+                                      [FeatureFMA4]>;
 def FeatureVectorUAMem : SubtargetFeature<"vector-unaligned-mem",
                                           "HasVectorUAMem", "true",
                  "Allow unaligned memory operands on vector/SIMD instructions">;
 def FeatureAES     : SubtargetFeature<"aes", "HasAES", "true",
-                                      "Enable AES instructions">;
+                                      "Enable AES instructions",
+                                      [FeatureSSE2]>;
+def FeatureTBM     : SubtargetFeature<"tbm", "HasTBM", "true",
+                                      "Enable TBM instructions">;
+def FeatureMOVBE   : SubtargetFeature<"movbe", "HasMOVBE", "true",
+                                      "Support MOVBE instruction">;
+def FeatureRDRAND  : SubtargetFeature<"rdrnd", "HasRDRAND", "true",
+                                      "Support RDRAND instruction">;
+def FeatureF16C    : SubtargetFeature<"f16c", "HasF16C", "true",
+                       "Support 16-bit floating point conversion instructions",
+                       [FeatureAVX]>;
+def FeatureFSGSBase : SubtargetFeature<"fsgsbase", "HasFSGSBase", "true",
+                                       "Support FS/GS Base instructions">;
+def FeatureLZCNT   : SubtargetFeature<"lzcnt", "HasLZCNT", "true",
+                                      "Support LZCNT instruction">;
+def FeatureBMI     : SubtargetFeature<"bmi", "HasBMI", "true",
+                                      "Support BMI instructions">;
+def FeatureBMI2    : SubtargetFeature<"bmi2", "HasBMI2", "true",
+                                      "Support BMI2 instructions">;
+def FeatureRTM     : SubtargetFeature<"rtm", "HasRTM", "true",
+                                      "Support RTM instructions">;
+def FeatureHLE     : SubtargetFeature<"hle", "HasHLE", "true",
+                                      "Support HLE">;
+def FeatureADX     : SubtargetFeature<"adx", "HasADX", "true",
+                                      "Support ADX instructions">;
+def FeatureSHA     : SubtargetFeature<"sha", "HasSHA", "true",
+                                      "Enable SHA instructions",
+                                      [FeatureSSE2]>;
+def FeaturePRFCHW  : SubtargetFeature<"prfchw", "HasPRFCHW", "true",
+                                      "Support PRFCHW instructions">;
+def FeatureRDSEED  : SubtargetFeature<"rdseed", "HasRDSEED", "true",
+                                      "Support RDSEED instruction">;
+def FeatureLeaForSP : SubtargetFeature<"lea-sp", "UseLeaForSP", "true",
+                                     "Use LEA for adjusting the stack pointer">;
+def FeatureSlowDivide : SubtargetFeature<"idiv-to-divb",
+                                     "HasSlowDivide", "true",
+                                     "Use small divide for positive values less than 256">;
+def FeaturePadShortFunctions : SubtargetFeature<"pad-short-functions",
+                                     "PadShortFunctions", "true",
+                                     "Pad short functions">;
+def FeatureCallRegIndirect : SubtargetFeature<"call-reg-indirect",
+                                     "CallRegIndirect", "true",
+                                     "Call register indirect">;
+def FeatureLEAUsesAG : SubtargetFeature<"lea-uses-ag", "LEAUsesAG", "true",
+                                   "LEA instruction needs inputs at AG stage">;
 
 //===----------------------------------------------------------------------===//
 // X86 processors supported.
 //===----------------------------------------------------------------------===//
 
+include "X86Schedule.td"
+
+def ProcIntelAtom : SubtargetFeature<"atom", "X86ProcFamily", "IntelAtom",
+                    "Intel Atom processors">;
+def ProcIntelSLM  : SubtargetFeature<"slm", "X86ProcFamily", "IntelSLM",
+                    "Intel Silvermont processors">;
+
 class Proc<string Name, list<SubtargetFeature> Features>
- : Processor<Name, NoItineraries, Features>;
+ : ProcessorModel<Name, GenericModel, Features>;
 
 def : Proc<"generic",         []>;
 def : Proc<"i386",            []>;
@@ -96,64 +191,171 @@ def : Proc<"i686",            []>;
 def : Proc<"pentiumpro",      [FeatureCMOV]>;
 def : Proc<"pentium2",        [FeatureMMX, FeatureCMOV]>;
 def : Proc<"pentium3",        [FeatureSSE1]>;
+def : Proc<"pentium3m",       [FeatureSSE1, FeatureSlowBTMem]>;
 def : Proc<"pentium-m",       [FeatureSSE2, FeatureSlowBTMem]>;
 def : Proc<"pentium4",        [FeatureSSE2]>;
-def : Proc<"x86-64",          [FeatureSSE2,   Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"yonah",           [FeatureSSE3, FeatureSlowBTMem]>;
-def : Proc<"prescott",        [FeatureSSE3, FeatureSlowBTMem]>;
-def : Proc<"nocona",          [FeatureSSE3,   Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"core2",           [FeatureSSSE3,  Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"penryn",          [FeatureSSE41,  Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"atom",            [FeatureSSE3,   Feature64Bit, FeatureSlowBTMem]>;
+def : Proc<"pentium4m",       [FeatureSSE2, FeatureSlowBTMem]>;
+
+// Intel Core Duo.
+def : ProcessorModel<"yonah", SandyBridgeModel,
+                     [FeatureSSE3, FeatureSlowBTMem]>;
+
+// NetBurst.
+def : Proc<"prescott", [FeatureSSE3, FeatureSlowBTMem]>;
+def : Proc<"nocona",   [FeatureSSE3, FeatureCMPXCHG16B, FeatureSlowBTMem]>;
+
+// Intel Core 2 Solo/Duo.
+def : ProcessorModel<"core2", SandyBridgeModel,
+                     [FeatureSSSE3, FeatureCMPXCHG16B, FeatureSlowBTMem]>;
+def : ProcessorModel<"penryn", SandyBridgeModel,
+                     [FeatureSSE41, FeatureCMPXCHG16B, FeatureSlowBTMem]>;
+
+// Atom.
+def : ProcessorModel<"atom", AtomModel,
+                     [ProcIntelAtom, FeatureSSSE3, FeatureCMPXCHG16B,
+                      FeatureMOVBE, FeatureSlowBTMem, FeatureLeaForSP,
+                      FeatureSlowDivide,
+                      FeatureCallRegIndirect,
+                      FeatureLEAUsesAG,
+                      FeaturePadShortFunctions]>;
+
+// Atom Silvermont.
+def : ProcessorModel<"slm",  SLMModel, [ProcIntelSLM,
+                               FeatureSSE42, FeatureCMPXCHG16B,
+                               FeatureMOVBE, FeaturePOPCNT,
+                               FeaturePCLMUL, FeatureAES,
+                               FeatureCallRegIndirect,
+                               FeaturePRFCHW,
+                               FeatureSlowBTMem, FeatureFastUAMem]>;
 // "Arrandale" along with corei3 and corei5
-def : Proc<"corei7",          [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem,
-                               FeatureFastUAMem, FeatureAES]>;
-def : Proc<"nehalem",         [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem,
-                               FeatureFastUAMem]>;
+def : ProcessorModel<"corei7", SandyBridgeModel,
+                     [FeatureSSE42, FeatureCMPXCHG16B, FeatureSlowBTMem,
+                      FeatureFastUAMem, FeaturePOPCNT, FeatureAES]>;
+
+def : ProcessorModel<"nehalem", SandyBridgeModel,
+                     [FeatureSSE42,  FeatureCMPXCHG16B, FeatureSlowBTMem,
+                      FeatureFastUAMem, FeaturePOPCNT]>;
 // Westmere is a similar machine to nehalem with some additional features.
 // Westmere is the corei3/i5/i7 path from nehalem to sandybridge
-def : Proc<"westmere",         [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem,
-                                FeatureFastUAMem, FeatureAES]>;
-// Sandy Bridge does not have FMA
-// FIXME: Wikipedia says it does... it should have AES as well.
-def : Proc<"sandybridge",     [FeatureSSE42,  FeatureAVX,   Feature64Bit]>;
+def : ProcessorModel<"westmere", SandyBridgeModel,
+                     [FeatureSSE42, FeatureCMPXCHG16B, FeatureSlowBTMem,
+                      FeatureFastUAMem, FeaturePOPCNT, FeatureAES,
+                      FeaturePCLMUL]>;
+// Sandy Bridge
+// SSE is not listed here since llvm treats AVX as a reimplementation of SSE,
+// rather than a superset.
+def : ProcessorModel<"corei7-avx", SandyBridgeModel,
+                     [FeatureAVX, FeatureCMPXCHG16B, FeatureFastUAMem,
+                      FeaturePOPCNT, FeatureAES, FeaturePCLMUL]>;
+// Ivy Bridge
+def : ProcessorModel<"core-avx-i", SandyBridgeModel,
+                     [FeatureAVX, FeatureCMPXCHG16B, FeatureFastUAMem,
+                      FeaturePOPCNT, FeatureAES, FeaturePCLMUL, FeatureRDRAND,
+                      FeatureF16C, FeatureFSGSBase]>;
+
+// Haswell
+def : ProcessorModel<"core-avx2", HaswellModel,
+                     [FeatureAVX2, FeatureCMPXCHG16B, FeatureFastUAMem,
+                      FeaturePOPCNT, FeatureAES, FeaturePCLMUL, FeatureRDRAND,
+                      FeatureF16C, FeatureFSGSBase, FeatureMOVBE, FeatureLZCNT,
+                      FeatureBMI, FeatureBMI2, FeatureFMA, FeatureRTM,
+                      FeatureHLE]>;
+
+// KNL
+// FIXME: define KNL model
+def : ProcessorModel<"knl", HaswellModel,
+                     [FeatureAVX512, FeatureERI, FeatureCDI, FeaturePFI,
+                      FeatureCMPXCHG16B, FeatureFastUAMem, FeaturePOPCNT,
+                      FeatureAES, FeaturePCLMUL, FeatureRDRAND, FeatureF16C,
+                      FeatureFSGSBase, FeatureMOVBE, FeatureLZCNT, FeatureBMI,
+                      FeatureBMI2, FeatureFMA, FeatureRTM, FeatureHLE]>;
 
 def : Proc<"k6",              [FeatureMMX]>;
-def : Proc<"k6-2",            [FeatureMMX,    Feature3DNow]>;
-def : Proc<"k6-3",            [FeatureMMX,    Feature3DNow]>;
-def : Proc<"athlon",          [FeatureMMX,    Feature3DNowA, FeatureSlowBTMem]>;
-def : Proc<"athlon-tbird",    [FeatureMMX,    Feature3DNowA, FeatureSlowBTMem]>;
-def : Proc<"athlon-4",        [FeatureSSE1,   Feature3DNowA, FeatureSlowBTMem]>;
-def : Proc<"athlon-xp",       [FeatureSSE1,   Feature3DNowA, FeatureSlowBTMem]>;
-def : Proc<"athlon-mp",       [FeatureSSE1,   Feature3DNowA, FeatureSlowBTMem]>;
+def : Proc<"k6-2",            [Feature3DNow]>;
+def : Proc<"k6-3",            [Feature3DNow]>;
+def : Proc<"athlon",          [Feature3DNowA, FeatureSlowBTMem,
+                               FeatureSlowSHLD]>;
+def : Proc<"athlon-tbird",    [Feature3DNowA, FeatureSlowBTMem,
+                               FeatureSlowSHLD]>;
+def : Proc<"athlon-4",        [FeatureSSE1,   Feature3DNowA, FeatureSlowBTMem, 
+                               FeatureSlowSHLD]>;
+def : Proc<"athlon-xp",       [FeatureSSE1,   Feature3DNowA, FeatureSlowBTMem,
+                               FeatureSlowSHLD]>;
+def : Proc<"athlon-mp",       [FeatureSSE1,   Feature3DNowA, FeatureSlowBTMem,
+                               FeatureSlowSHLD]>;
 def : Proc<"k8",              [FeatureSSE2,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
 def : Proc<"opteron",         [FeatureSSE2,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
 def : Proc<"athlon64",        [FeatureSSE2,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
 def : Proc<"athlon-fx",       [FeatureSSE2,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
-def : Proc<"k8-sse3",         [FeatureSSE3,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
-def : Proc<"opteron-sse3",    [FeatureSSE3,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
-def : Proc<"athlon64-sse3",   [FeatureSSE3,   Feature3DNowA, Feature64Bit,
-                               FeatureSlowBTMem]>;
-def : Proc<"amdfam10",        [FeatureSSE3,   FeatureSSE4A,
-                               Feature3DNowA, Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"barcelona",       [FeatureSSE3,   FeatureSSE4A,
-                               Feature3DNowA, Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"istanbul",        [Feature3DNowA, Feature64Bit, FeatureSSE4A,
-                               Feature3DNowA]>;
-def : Proc<"shanghai",        [Feature3DNowA, Feature64Bit, FeatureSSE4A,
-                               Feature3DNowA]>;
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
+def : Proc<"k8-sse3",         [FeatureSSE3,   Feature3DNowA, FeatureCMPXCHG16B,
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
+def : Proc<"opteron-sse3",    [FeatureSSE3,   Feature3DNowA, FeatureCMPXCHG16B,
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
+def : Proc<"athlon64-sse3",   [FeatureSSE3,   Feature3DNowA, FeatureCMPXCHG16B,
+                               FeatureSlowBTMem, FeatureSlowSHLD]>;
+def : Proc<"amdfam10",        [FeatureSSE4A,
+                               Feature3DNowA, FeatureCMPXCHG16B, FeatureLZCNT,
+                               FeaturePOPCNT, FeatureSlowBTMem,
+                               FeatureSlowSHLD]>;
+// Bobcat
+def : Proc<"btver1",          [FeatureSSSE3, FeatureSSE4A, FeatureCMPXCHG16B,
+                               FeaturePRFCHW, FeatureLZCNT, FeaturePOPCNT,
+                               FeatureSlowSHLD]>;
+// Jaguar
+def : Proc<"btver2",          [FeatureAVX, FeatureSSE4A, FeatureCMPXCHG16B,
+                               FeaturePRFCHW, FeatureAES, FeaturePCLMUL,
+                               FeatureBMI, FeatureF16C, FeatureMOVBE,
+                               FeatureLZCNT, FeaturePOPCNT, FeatureSlowSHLD]>;
+// Bulldozer
+def : Proc<"bdver1",          [FeatureXOP, FeatureFMA4, FeatureCMPXCHG16B,
+                               FeatureAES, FeaturePRFCHW, FeaturePCLMUL,
+                               FeatureLZCNT, FeaturePOPCNT, FeatureSlowSHLD]>;
+// Piledriver
+def : Proc<"bdver2",          [FeatureXOP, FeatureFMA4, FeatureCMPXCHG16B,
+                               FeatureAES, FeaturePRFCHW, FeaturePCLMUL,
+                               FeatureF16C, FeatureLZCNT,
+                               FeaturePOPCNT, FeatureBMI, FeatureTBM,
+                               FeatureFMA, FeatureSlowSHLD]>;
+
+// Steamroller
+def : Proc<"bdver3",          [FeatureXOP, FeatureFMA4, FeatureCMPXCHG16B,
+                               FeatureAES, FeaturePRFCHW, FeaturePCLMUL,
+                               FeatureF16C, FeatureLZCNT,
+                               FeaturePOPCNT, FeatureBMI,  FeatureTBM,
+                               FeatureFMA, FeatureFSGSBase]>;
+
+// Excavator
+def : Proc<"bdver4",          [FeatureAVX2, FeatureXOP, FeatureFMA4,
+                               FeatureCMPXCHG16B, FeatureAES, FeaturePRFCHW,
+                               FeaturePCLMUL, FeatureF16C, FeatureLZCNT,
+                               FeaturePOPCNT, FeatureBMI, FeatureBMI2,
+                               FeatureTBM, FeatureFMA, FeatureFSGSBase]>;
+
+def : Proc<"geode",           [Feature3DNowA]>;
 
 def : Proc<"winchip-c6",      [FeatureMMX]>;
-def : Proc<"winchip2",        [FeatureMMX, Feature3DNow]>;
-def : Proc<"c3",              [FeatureMMX, Feature3DNow]>;
+def : Proc<"winchip2",        [Feature3DNow]>;
+def : Proc<"c3",              [Feature3DNow]>;
 def : Proc<"c3-2",            [FeatureSSE1]>;
 
+// We also provide a generic 64-bit specific x86 processor model which tries to
+// be good for modern chips without enabling instruction set encodings past the
+// basic SSE2 and 64-bit ones. It disables slow things from any mainstream and
+// modern 64-bit x86 chip, and enables features that are generally beneficial.
+// 
+// We currently use the Sandy Bridge model as the default scheduling model as
+// we use it across Nehalem, Westmere, Sandy Bridge, and Ivy Bridge which
+// covers a huge swath of x86 processors. If there are specific scheduling
+// knobs which need to be tuned differently for AMD chips, we might consider
+// forming a common base for them.
+def : ProcessorModel<"x86-64", SandyBridgeModel,
+                     [FeatureSSE2, Feature64Bit, FeatureSlowBTMem,
+                      FeatureFastUAMem]>;
+
 //===----------------------------------------------------------------------===//
 // Register File Description
 //===----------------------------------------------------------------------===//
@@ -179,11 +381,16 @@ include "X86CallingConv.td"
 // Assembly Parser
 //===----------------------------------------------------------------------===//
 
-// Currently the X86 assembly parser only supports ATT syntax.
 def ATTAsmParser : AsmParser {
-  string AsmParserClassName = "ATTAsmParser";
+  string AsmParserClassName = "AsmParser";
+}
+
+def ATTAsmParserVariant : AsmParserVariant {
   int Variant = 0;
 
+  // Variant name.
+  string Name = "att";
+
   // Discard comments in assembly strings.
   string CommentDelimiter = "#";
 
@@ -191,6 +398,19 @@ def ATTAsmParser : AsmParser {
   string RegisterPrefix = "%";
 }
 
+def IntelAsmParserVariant : AsmParserVariant {
+  int Variant = 1;
+
+  // Variant name.
+  string Name = "intel";
+
+  // Discard comments in assembly strings.
+  string CommentDelimiter = ";";
+
+  // Recognize hard coded registers.
+  string RegisterPrefix = "";
+}
+
 //===----------------------------------------------------------------------===//
 // Assembly Printers
 //===----------------------------------------------------------------------===//
@@ -200,19 +420,16 @@ def ATTAsmParser : AsmParser {
 def ATTAsmWriter : AsmWriter {
   string AsmWriterClassName  = "ATTInstPrinter";
   int Variant = 0;
-  bit isMCAsmWriter = 1;
 }
 def IntelAsmWriter : AsmWriter {
   string AsmWriterClassName  = "IntelInstPrinter";
   int Variant = 1;
-  bit isMCAsmWriter = 1;
 }
 
 def X86 : Target {
   // Information about the instructions...
   let InstructionSet = X86InstrInfo;
-
   let AssemblyParsers = [ATTAsmParser];
-
+  let AssemblyParserVariants = [ATTAsmParserVariant, IntelAsmParserVariant];
   let AssemblyWriters = [ATTAsmWriter, IntelAsmWriter];
 }